[4-(2-Ethoxy-2-oxoethylidene)cyclohexa-2,5-dien-1-ylidene]-methyloxidanium | 136878-04-1

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: [4-(2-Ethoxy-2-oxoethylidene)cyclohexa-2,5-dien-1-ylidene]-methyloxidanium
• CAS: 136878-04-1
• 化学式: C₁₁H₁₃O₃
• 分子量: 193.222
• InChiKey: AXLAUCJPIBPYIN-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  1
• 重原子数：
  14
• 可旋转键数：
  3
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.27
• 拓扑面积：
  27.3
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为反应物：
  描述：

  [4-(2-Ethoxy-2-oxoethylidene)cyclohexa-2,5-dien-1-ylidene]-methyloxidanium 在 水 、 三氟乙酸 作用下， 生成 ethyl 2-hydroxy-2-(4-methoxyphenyl)acetate
  参考文献：
  名称：

  Generation and determination of the lifetime of an α-carbonyl substituted carbocation

  摘要：

  The alpha-carboxyethyl-4-methoxybenzyl carbocation reacts with a solvent of 50:50 (v:v) trifluoroethanol/water with a rate constant k(S) = 1.4 x 10(7) s-1, which is 14-fold slower than the capture of the unsubstituted 4-methoxybenzyl carbocation.

  DOI：

  10.1016/s0040-4039(00)92142-7
• 作为产物：
  描述：

  α-(ethoxycarbonyl)-4-methoxybenzyl alcohol pentafluorobenzoate ester 在 sodium perchlorate 、 水 、 三氟乙酸 作用下， 生成 [4-(2-Ethoxy-2-oxoethylidene)cyclohexa-2,5-dien-1-ylidene]-methyloxidanium
  参考文献：
  名称：

  Generation and determination of the lifetime of an α-carbonyl substituted carbocation

  摘要：

  The alpha-carboxyethyl-4-methoxybenzyl carbocation reacts with a solvent of 50:50 (v:v) trifluoroethanol/water with a rate constant k(S) = 1.4 x 10(7) s-1, which is 14-fold slower than the capture of the unsubstituted 4-methoxybenzyl carbocation.

  DOI：

  10.1016/s0040-4039(00)92142-7

文献信息

• The effects of .alpha.-substituents on the kinetic and thermodynamic stability of 4-methoxybenzyl carbocations: carbocation lifetimes that are independent of their thermodynamic stability
  作者：Tina L. Amyes、Ishmael W. Stevens、John P. Richard

  DOI：10.1021/jo00074a036

  日期：1993.10

  The following new rate constants for reaction of alpha-substituted 4-methoxybenzyl carbocations, 4-MeOC6H4CR1(R2)+, With a solvent of 50:50 (v/v) trifluoroethanol/water at 25-degrees-C and ionic strength 0.50 (NaClO4) are reported: 4-MeOC6H4CH(OMe)+, k(S) = 2.2 X 10(7) s-1; 4-MeOC6H4CH(N3)+, k(S) = 3.3 X 10(5) s-1; 4-MeOC6H4C(CH3)2+, k(S) = 1.3 x 10(7) s-1; 4-MeOC6H4CH(CO2Et)+, k(S) = 1.4 X 10(7) s-1; 4-MeOC6H4CCH3(CF3)+, k(S) = 2.5 x 10(7) s-1. The values of k(S) for reaction of 4-MeOC6H4CR1(R2)+ with 50:50 (v/v) trifluoroethanol/water are nearly independent of very large changes in the thermodynamic stability of these carbocations caused by the addition of a wide range of electron-withdrawing or electron-donating groups at the alpha-position. In the most extreme case, the change from an alpha-methoxy to two alpha-(trifluoromethyl) substituents leads to a 23 kcal/mol thermodynamic destabilization of 4-MeOCrH4CR1(R2)+ relative to the neutral azide ion adducts but a 5-fold decrease in its reactivity toward solvent. The data show that the effects of alpha-substituents on the kinetic stability of 4-MeOC6H4CR1(R2)+ are complex and do not parallel the thermodynamic stability of these carbocations. The results are explained by consideration of the polar and resonance effects of the alpha-substituents on both the thermodynamic driving force and the intrinsic barrier for capture of the carbocations by solvent. These reactions are a new example of the consequences of the ''principle of nonperfect synchronization''.41